"Randy Zimmerman" wrote in message
news:eS_zd.577833$Pl.276235@pd7tw1no...
I am getting some good ideas. We have used our punching dies from the
ironworker for larger transfer punches in some cases.
In most of my situations the pieces I drill are heavy being over 100
pounds. Recently I was doing stacked drilled 3.75 thick plate. It took
as much time to load and align as to drill the nine holes. We used a
quarter inch plate masterpunched and transferred with punch dies.
On this coming job I will try the transfer punch idea. I have not had
much luck using a split point on large bits and starting on the centerpop.
I have been using centerdrill first then changing bits when the arm is
locked.

There's no doubt it is ideal to c-drill, pilot and then drill to full
diameter (or even double drill), but that takes time. In your situation, it
would take a lot of time. This is why it is critical to know if the sets
must match only themselves, or all the other plates as well.

When drilling large-ish holes in steel with a hand drill, you really start
to understand why they sell split-point drills. Correctly ground, these
significantly reduce the power required to drill a hole. Naturally, if they
are incorrectly ground, you're going to lose your edge prematurely, or the
drill will wander, or, or, or...

This is the kind of job where a well thought out work plan and efficient
fixturing will save lots of time.

Good luck, and of course let us know how you make out.

Regards,

Robin